Struggling Walsall crashed to the their second home defeat in a week as Colchester ran out 1-0 winners.
The Us picked up all three points when Andy Bond was left unmarked at the far post to head in a perfect cross from Brian Wilson seven minutes from time.
Saddlers substitute Darren Byfield should have salvaged a point in the 88th minute when he burst through the middle and rounded keeper Mark Cousins, but he drove his shot over the bar from an angle.
But Colchester always looked the more likely to snatch the points, and substitute Kayode Odejayi shot wide from a good position before Bond struck.
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